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A kumquat is a small, olive-sized citrus fruit that you eat whole, peel and all. That single habit is what makes the kumquat fruit different from an orange: the thin peel is part of the bite, so you get the fiber and aroma of the rind along with the tart flesh inside. In USDA data, one kumquat weighs about 19 grams and has roughly 13 calories. This guide explains how to eat kumquats, what USDA lists for kumquat nutrition, how it compares with other citrus, and what the (very limited) research on kumquat benefits actually covers.
Peptide Labs does not sell kumquats or kumquat products. This article is general nutrition information, not medical advice.
Key Takeaways
- Kumquats are tiny citrus fruits eaten whole; the peel is edible and most of the fiber comes with it.
- Per 100 grams, USDA lists 71 calories, 6.5 grams of fiber (23% DV) and about half the Daily Value for vitamin C.
- One kumquat has about 13 calories and 1.8 grams of sugar in USDA data.
- Human research on kumquats is scarce; most studies look at plant chemistry, lab tests or mice.
- Kumquat allergy is rare but a 2024 case report described anaphylaxis.
What is a kumquat?
Kumquats are citrus fruits from small evergreen trees long grown in East Asia. Older papers place them in their own genus, Fortunella, while newer papers often use the name Citrus japonica. You may see both on seed catalogs and in research. Varieties named in recent studies include Nagami and the Chinese Changshou, Liuyang and Huapi kumquats.
The fruit is oval or round, orange when ripe, and about the size of a large olive. The flavor is a contrast: the peel tastes sweet and fragrant, and the juicy center is sour. A 2025 study of three kumquat varieties found that sweetness and bitterness were driven mainly by the fruit’s sucrose and by limonin, a bitter citrus compound that was more concentrated in the seeds than in the peel. That fits the common advice to spit out or remove the seeds.
Kumquat nutrition: USDA values
The table below uses the USDA SR Legacy entry for raw kumquats (FDC 168154). Because the whole fruit is eaten, the numbers include the peel. Percent Daily Values use the FDA Daily Values printed on Nutrition Facts labels.
| Nutrient | 1 kumquat (19 g) | 5 kumquats (95 g) | Per 100 g | %DV per 100 g |
|---|---|---|---|---|
| Calories | 13 | 67 | 71 | n/a |
| Carbohydrate | 3.0 g | 15.1 g | 15.9 g | 6% |
| Fiber | 1.2 g | 6.2 g | 6.5 g | 23% |
| Total sugars | 1.8 g | 8.9 g | 9.4 g | n/a |
| Protein | 0.4 g | 1.8 g | 1.9 g | 4% |
| Vitamin C | 8 mg | 42 mg | 44 mg | 49% |
| Calcium | 12 mg | 59 mg | 62 mg | 5% |
| Potassium | 35 mg | 177 mg | 186 mg | 4% |
| Copper | 0.02 mg | 0.09 mg | 0.10 mg | 11% |
| Magnesium | 4 mg | 19 mg | 20 mg | 5% |
| Iron | 0.2 mg | 0.8 mg | 0.9 mg | 5% |
Two numbers stand out. First, fiber: 6.5 grams per 100 grams is unusually high for a fruit, and the edible peel is the reason. Second, vitamin C: five kumquats supply close to half the Daily Value, per USDA. Calcium is also a little higher than in most citrus, though still a small share of the Daily Value. For more fruit options by nutrient, see our guides to high fiber foods, foods high in vitamin C, and how much fiber per day for the reference values behind the fiber Daily Value.
Kumquat vs orange, tangerine and lemon
Per 100 grams, kumquats carry more calories and much more fiber than other common citrus, mostly because you eat the peel. Values are from USDA SR Legacy.
| Fruit (raw, per 100 g) | Calories | Fiber | Sugars | Vitamin C | Calcium |
|---|---|---|---|---|---|
| Kumquat (168154) | 71 | 6.5 g | 9.4 g | 44 mg | 62 mg |
| Orange (169097) | 47 | 2.4 g | 9.4 g | 53 mg | 40 mg |
| Tangerine (169105) | 53 | 1.8 g | 10.6 g | 27 mg | 37 mg |
| Lemon, no peel (167746) | 29 | 2.8 g | 2.5 g | 53 mg | 26 mg |
| Pomelo (167754) | 38 | 1.0 g | not listed | 61 mg | 4 mg |
Sugar per 100 grams is about the same as an orange, but a single kumquat is so small that one fruit holds under 2 grams of sugar. If you are comparing fruit by sugar content, our low sugar fruits guide uses the same USDA source. At the other end of the citrus size scale is the pomelo, which can weigh more than 30 kumquats.
How to eat kumquats
The short answer: rinse them and eat them whole. There is no peeling step. Here are the common ways people use them:
- Raw and whole. Wash, pull off any stem or leaf, and bite in. Many people start with the peel end to get the sweet rind first, then the sour center.
- Halved and seeded. Cut each fruit in half lengthwise and flick out the seeds with a knife tip. The seeds are edible but bitter, which matches the limonin finding above.
- Sliced into salads. Thin rounds add a sharp citrus note to green salads, grain bowls or salsas.
- Cooked. Kumquats are often simmered into marmalade or candied in syrup. That adds a lot of sugar, so check the Nutrition Facts label on jarred versions; USDA SR Legacy has no entry for candied kumquats.
- With savory dishes. Roasted with chicken or pork, or chopped into a relish.
Pick fruit that is firm, glossy and fully orange; green patches mean it is underripe and more sour. Store them in the refrigerator and rinse just before eating.
Kumquat benefits: what the research shows
Honest answer: very little of the research is about people eating kumquats. Most studies are about growing the trees, the fruit’s chemistry, or lab and animal tests. Here is what that work covers:
- Plant compounds. A 2025 study that profiled 1,719 metabolites in three varieties found flavonoids more abundant in the peel than in the seeds, and red-skinned fruit richer in anthocyanin and carotenoid compounds. That is chemistry, not proof of a health effect.
- Essential oil. A 2024 study described the chemical profile of kumquat peel oil and its activity in lab tests and simulated digestion.
- Animal research. A 2025 study in mice fed a high-fat diet reported that kumquat fruit supplementation changed markers of brain insulin signalling and inflammation. Mouse results often do not carry over to people, and no human trial has tested this.
What we can say with confidence comes from the USDA numbers: kumquats are a low-calorie fruit that provides fiber and vitamin C, like many fruits in a varied diet. Our foods high in antioxidants guide explains why test-tube antioxidant scores do not translate directly into benefits in the body.
Safety: allergy, medicines and fiber
- Allergy. Citrus is not one of the nine major food allergens under US law, but reactions happen. A 2024 case report in the European Journal of Dermatology described anaphylaxis to kumquat. If you react to citrus, ask an allergist before trying it, and see our elimination diet guide for why self-testing is not a substitute.
- Medicines. The FDA warns that grapefruit can interfere with some medicines and names Seville oranges, pomelos and tangelos as fruits that might act the same way. Kumquats are not on that list, and we found no published reports of kumquat interactions. If your medicine carries a grapefruit warning, ask your pharmacist about other citrus too.
- Fiber. Because the peel is eaten, a big handful adds noticeable fiber. If you are not used to fiber, increase slowly and drink fluids to limit gas or bloating.
- Pesticide residue. Since the peel is eaten, rinse the fruit well under running water.
Frequently Asked Questions
Do you eat the skin of a kumquat?
Yes. The peel is edible and is the sweet part of the fruit. The flesh inside is sour. Most people eat the whole fruit and spit out or remove the seeds.
How many calories are in a kumquat?
About 13 calories per fruit, based on the USDA entry for raw kumquats and a 19 gram fruit.
Are kumquats high in fiber?
For a fruit, yes. USDA lists 6.5 grams of fiber per 100 grams, which is 23% of the Daily Value, largely because the peel is eaten.
Can you eat kumquat seeds?
They are not harmful in the small amounts found in the fruit, but they taste bitter. Many people remove them.
Are kumquats a type of orange?
They are citrus but not oranges. Older botanical papers put kumquats in the genus Fortunella; newer ones often call them Citrus japonica.
Do kumquats interact with medications like grapefruit?
The FDA’s grapefruit warning names Seville oranges, pomelos and tangelos, not kumquats. If your medicine has a grapefruit warning, ask your pharmacist whether any citrus is a concern.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Pomelo: Pomelo Fruit Nutrition, Pomelo vs Grapefruit and Safety, Foods High in Vitamin C: USDA List of Fruits and Vegetables, High Fiber Foods: USDA List of Fruits, Vegetables, Beans and Grains.